Document WO-01/00296 describes an example of a separation device comprising a first separator comprising in series in a longitudinal direction of flow, an inlet for a mixture of a liquid and gas, an accelerator for rotating the said mixture, a separation chamber and a liquid outlet. By a cyclonic effect, a gaseous phase of the mixture is concentrated in the centre of the separation chamber in the form of a gas cylinder, surrounded by a liquid phase. This separator comprises a gas outlet at the centre of the separation chamber for extracting the gas.
However, some liquid is drawn towards the central zone and the extracted gas still comprises a fraction of liquid.
In order to improve the separation, the separation device of the document WO-01/00296 then comprises a second separator of the gravity type, fed by the gas outlet of the first separator.
Such a separation device is then bulky and costly.